The experiment was carried out from October to December 2000, in Mossoró, Brazil. The experimental design was of randomized complete blocks in a 3 x 4 + 1 factorial scheme with four replications. The treatments consisted of the combination of three cropping systems (S1= sole crop; S2 = three carrot rows alternated with three lettuce rows; and S3= four carrot rows alternated with four lettuce rows), with four looseleaf lettuce cultivars (Babá de Verão, Karla, Verdinha and Elisabeth), plus an additional treatment (carrot, cv. Brasília, in sole crop). Evaluations of plant height and diameter, number of leaves per plant and leaf dry matter and yield were made for lettuce crop. Plant height, shoot fresh matter, total, commercial and classification of roots were obtained for the carrot crop. Agroeconomic indices were used to measure the efficiency of intercropping systems. No significant interaction between cropping systems and lettuce cultivars for any lettuce and carrot characteristic was obtained. The cropping system influenced all lettuce and carrot traits and lettuce cultivars affected only the leaf number/plant, being higher for cultivar 'Karla'. The yield of lettuce in the intercropping systems, although lower than for the sole crop, represented an additional income source. The intercropping of 'Brasília' carrot x lettuce cultivar 'Verdinha' in the strip arrangement of four carrot rows alternated with four lettuce rows showed a greater agroeconomic efficiency, with a land equivalent ratio of 1.19 and a 3,0 as return rate.
Lactuca sativa; Daucus carota; agronomic efficiency; relative advantage
